Effect of Solution and Aging Treatment on Microstructure and Properties of TC4 Titanium Alloy Hot-Rolled Sheet by Sponge Titanium/Electrolytic Titanium Melting

Sponge titanium and electrolytic titanium were used as raw materials for melting TC4 titanium alloy. The smelted ingot was subjected to hot rolling and solution aging treatment. The microstructure and properties of TC4 titanium alloy sheet rolled from ingots of different raw materials after different solid solution aging treatments were studied. The results show that the a alpha ->beta transition of sponge titanium TC4 and electrolytic titanium TC4 alloys is an endothermic process. The transformation point temperature of electrolytic titanium TC4 is obviously higher than that of sponge titanium TC4. When the sponge titanium TC4 alloy is solid-solved at a temperature exceeding the transformation point temperature, its structure is Weiss-structure. Other structures under different solid-solution aging conditions are all bimorphic. After solid solution aging treatment, the tensile strength of sponge titanium TC4 increases at first and then decreases, while the elongation continues to decrease with the increase of the solution temperature. The tensile strength of electrolytic titanium TC4 increases with increasing solution temperature, while the elongation continues to decrease. Both of them obtain the best comprehensive mechanical properties after solid solution holding at 890 degrees C for 30 min and 550 degrees C for 3 h. Compared with sponge titanium TC4, the electrolytic titanium TC4 has a more significant improvement in strength and hardness after solid solution aging treatment.